Methods and systems for determining refractive corrections of human eyes for eyeglasses

ABSTRACT

Methods, devices, and systems are disclosed for determining refractive corrections of human eyes to reduce and eliminate image distortion associated with eyeglasses. In some embodiments, an objective refraction module is configured to measure refractive errors of an eye objectively, without subjective feedback from a tested subject. A computation module is configured to generate a plurality of objective prescriptions. A phoropter module is configured to perform a subjective refraction for determining a plurality of subjective spherical powers based on the plurality of objective prescriptions. An output module is configured to generate a plurality of prescriptions for eyeglasses, the plurality of prescriptions comprising (a) a first prescription having a first subjective spherical power f s1 , a first objective cylinder power F c1 , and a first objective cylinder angle F a1 , and (b) a second prescription having a second subjective spherical power f s2 , a second objective cylinder power F c2 , and a second objective cylinder angle F a2 .

RELATED APPLICATIONS

This application 1) is a divisional of U.S. patent application Ser. No.15/631,935, filed Jun. 23, 2017 and entitled “Methods and Systems forDetermining Refractive Corrections of Human Eyes for Eyeglasses”; which2) is a continuation of International Patent Application No.PCT/US17/30784, filed on May 3, 2017 and entitled “Methods and Systemsfor Determining Refractive Corrections of Human Eyes for Eyeglasses”;which claims priority from 3) U.S. patent application Ser. No.15/151,491, filed on May 11, 2016, and entitled “Methods and Systems forDetermining Refractive Corrections of Human Eyes for Eyeglasses; all ofwhich are hereby incorporated by reference for all purposes.

BACKGROUND OF THE INVENTION

Consumers often have to adapt to a new pair of eyeglasses which is aknown issue in the eyeglasses industry. It often relates to imagedistortion of the new eyeglasses, and adaptation to new eyeglasses cansometimes be a very painful process for some people. Three consequenceshappen when the image distortion by eyeglasses is not handled properly.First, a pair of new eyeglasses may take 1 to 2 week(s) for consumers toget used to, with the individual's experience varying from person toperson. Second, a significant portion of new eyeglasses purchased areabandoned because consumers can never become accustomed to them. Thiscauses monetary losses because a new pair of eyeglasses does improve anindividual's vision, and getting used to the new eyeglasses isconsidered a personal responsibility. Third, a population of peopleabandon eyeglasses all together if they fail to get used to alleyeglasses from different eyeglass shops.

The conventional refraction process shown in FIG. 1 relies on experienceand skills of an individual optometrist (optician) to set a startingpoint as well as an ending point for the prescription of eyeglasses.First, an autorefractor 11 is typically used to get an objectivemeasurement of an eye's refractive errors and provide a rough objectiveprescription 12 including a spherical power F_(s), a cylinder powerF_(c) and a cylinder angle F_(a). Second, an optometrist (or anoptician) will determine a rough spherical correction in a phoropter 13,and then adminstrates a subjective optimization of spherical power,cylinder power and cylinder angle based on the objective prescription.The subjective optimization is based on the experience and skill of theoptometrist or optician, and on subjective feedback of the testedsubjects (i.e., the patient). In step 16 of subjective refraction, thecylinder angle is subjectively optimized by letting the tested subjectfirst see an astigmatism chart and then an acuity chart afterwards. Theoptometrist (an optician) will set/modify the cylinder angle based onthe objective prescription as well as feedback of the tested subject. Instep 17 of subjective refraction, the cylinder power is subjectivelyoptimized by having the tested subject view an acuity chart, and anoptometrist (an optician) will set/modify the cylinder power based onthe objective prescription as well as feedback of the tested subject. Instep 18 of subjective refraction, the spherical power is subjectivelyoptimized by letting the tested subject see an acuity chart, and anoptometrist (an optician) will set/modify the spherical power based onfeedback of the tested subject. The same process is repeated for theother eye of the tested subject. Third, a final prescription of theeyeglasses (subjective refraction 14) is determined for each eye withthe subjectively optimized spherical power F_(s), subjectively optimizedcylinder power F_(c), and subjectively optimized cylinder angle F_(a).This conventional method of refraction does serve the purpose ofimproving vision with the new pair of eyeglasses. However, it is adifferent matter whether the tested subject will like the improvedvision with the new pair of eyeglasses purchased.

Consequently, although many configurations and methods for visioncorrection are known in the art, there is a need to provide improvedmethods and devices to reduce and eliminate image distortion associatedwith eyeglasses.

SUMMARY OF THE INVENTION

In some embodiments, a method for determining refractive prescriptionfor eyeglasses is provided. An objective refraction device is used tomeasure refractive errors of an eye of a tested subject objectively,where the objective refraction device excludes subjective feedback fromthe tested subject. A plurality of objective prescriptions for thetested subject is generated from the refractive errors of the eyemeasured objectively. The plurality of objective prescriptions includes(i) a first objective prescription having a first objective sphericalpower F_(s1), a first objective cylinder power F_(c1), and a firstobjective cylinder angle F_(a1), and (ii) a second objectiveprescription having a second objective spherical power F_(s2), a secondobjective cylinder power F_(c2), and a second objective cylinder angleF_(a2). The first objective cylinder power F_(c1) and the firstobjective cylinder angle F_(a1) of the first objective prescription areoptimized for image quality, and the second objective cylinder powerF_(c2) and the second objective cylinder angle F_(a2) of the secondobjective prescription are determined for a reduced image qualitycompared to that of the first objective prescription, or for obtainingreduced magnification differences at different orientations. A phoropteris used to perform a subjective refraction to determine a plurality ofsubjective spherical powers. The plurality of subjective sphericalpowers includes a first subjective spherical power f_(s1) and a secondsubjective spherical power f_(s2). The phoropter has a plurality ofspherical lenses and cylindrical lenses, where control of thecylindrical lenses is based only on the plurality of objectiveprescriptions. The subjective refraction requires subjective feedbackfrom the tested subject reading a chart through the phoropter. Aplurality of prescriptions for eyeglasses is generated from theplurality of objective prescriptions and the subjective refraction. Theplurality of prescriptions for eyeglasses includes (a) a firstprescription having the first subjective spherical power f_(s1), thefirst objective cylinder power F_(a1), and the first objective cylinderangle F_(a1), and (b) a second prescription having the second subjectivespherical power f_(s2), the second objective cylinder power F_(c2), andthe second objective cylinder angle F_(a2).

In some embodiments, a system for determining refractive prescriptionfor eyeglasses includes an objective refraction module and a computationmodule. The objective refraction module is configured to measurerefractive errors of an eye of a tested subject objectively, withoutsubjective feedback from the tested subject. The computation module isconfigured to generate a plurality of objective prescriptions for thetested subject from the refractive errors of the eye measuredobjectively. The plurality of objective prescriptions includes (i) afirst objective prescription having a first objective spherical powerF_(s1), a first objective cylinder power F_(c1), and a first objectivecylinder angle F_(a1), and (ii) a second objective prescription having asecond objective spherical power F_(s2), a second objective cylinderpower F_(c2), and a second objective cylinder angle F_(a2). The firstobjective cylinder power F_(c1) and the first objective cylinder angleF_(a1) of the first objective prescription are optimized for imagequality, while the second objective cylinder power F_(c2) and the secondobjective cylinder angle F_(a2) of the second objective prescription aredetermined for a reduced image quality compared to that of the firstobjective prescription, or for obtaining reduced magnificationdifferences at different orientations. In certain embodiments, thesystem also includes a phoropter module and an output module. Thephoropter module is configured to perform a subjective refraction fordetermining a plurality of subjective spherical powers based on theplurality of objective prescriptions from the computation module. Theplurality of subjective spherical powers includes a first subjectivespherical power f_(s1) and a second subjective spherical power f_(s2).The phoropter module has a plurality of spherical lenses and cylindricallenses, where control of the cylindrical lenses is based only on theplurality of objective prescriptions. The subjective refraction requiressubjective feedback from the tested subject reading a chart through thephoropter module. The output module is configured to generate aplurality of prescriptions for eyeglasses from the plurality ofobjective prescriptions and the subjective refraction. The plurality ofprescriptions includes (a) a first prescription having the firstsubjective spherical power f_(s1), the first objective cylinder powerF_(c1), and the first objective cylinder angle F_(a1), and (b) a secondprescription having the second subjective spherical power f_(s2), thesecond objective cylinder power F_(c2), and the second objectivecylinder angle F_(a2).

In some embodiments, a system for determining refractive prescription ofeyeglasses includes an input device module, a computation module, aphoropter module and an output module. The input device module isconfigured to receive a refractive data set of an eye of a testedsubject. The computation module is configured to generate a plurality ofinitial prescriptions for the eye from the refractive data set, wherethe plurality of initial prescriptions includes (i) a first initialprescription having a first initial spherical power F_(s1), a firstinitial cylinder power F_(c1), and a first initial cylinder angleF_(a1), and (ii) a second initial prescription having a second initialspherical power F_(s2), a second initial cylinder power F_(c2), and asecond initial cylinder angle F_(a2). The first initial cylinder powerF_(c1) and the first initial cylinder angle F_(a1) of the first initialprescription are optimized for image quality, and the second initialcylinder power F_(c2) and the second initial cylinder angle F_(a2) ofthe second initial prescription are determined for a reduced imagequality compared to that of the first initial prescription, or forobtaining reduced magnification differences at different orientations.The phoropter module is configured to perform a subjective refractionfor determining a plurality of subjective spherical powers based on theplurality of initial prescriptions. The plurality of subjectivespherical powers includes a first subjective spherical power f_(s1) anda second subjective spherical power f_(s2). The phoropter has aplurality of spherical lenses and cylindrical lenses, where control ofthe cylindrical lenses is based only on the plurality of initialprescriptions. The subjective refraction requires subjective feedbackfrom the tested subject reading a chart through the phoropter. Theoutput module is configured to generate a plurality of prescriptions foreyeglasses from the plurality of objective prescriptions and thesubjective refraction, the plurality of prescriptions including (a) afirst prescription having the first subjective spherical power f_(s1),the first initial cylinder power F_(c1), and the first initial cylinderangle F_(a1), and (b) a second prescription having the second subjectivespherical power f_(s2), the second initial cylinder power F_(c2), andthe second initial cylinder angle F_(a2).

In some embodiments, a system for determining refractive prescription ofeyeglasses includes an input device module, a phoropter module and anoutput module. The input device module is configured to receive aplurality of initial prescriptions. The plurality of initialprescriptions includes (i) a first initial prescription having a firstinitial spherical power F_(s1), a first initial cylinder power F_(c1),and a first initial cylinder angle F_(a1), and (ii) a second initialprescription having a second initial spherical power F_(s2), a secondinitial cylinder power F_(c2), and a second initial cylinder angleF_(a2). The phoropter module is configured to perform a subjectiverefraction for determining a plurality of subjective spherical powersbased on the plurality of initial prescriptions. The plurality ofsubjective spherical powers includes a first subjective spherical powerf_(s1) and a second subjective spherical power f_(s2). The phoroptermodule includes a plurality of spherical lenses and cylindrical lenses,where control of the cylindrical lenses is based only on the pluralityof initial prescriptions. The subjective refraction requires subjectivefeedback from the tested subject reading a chart through the phoroptermodule. The output module is configured to generate a plurality ofprescriptions for eyeglasses from the plurality of initial prescriptionsand the subjective refraction, the plurality of prescriptions including(a) a first prescription having the first subjective spherical powerf_(s1), the first initial cylinder power F_(c1), and the first initialcylinder angle F_(a1), and (b) a second prescription having the secondsubjective spherical power f_(s2), the second initial cylinder powerF_(c2), and the second initial cylinder angle F_(a2).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart for a conventional method of determiningrefractive prescription of eyeglasses known in the art.

FIG. 2 shows a flowchart for a wavefront method used for determiningrefractive prescription of eyeglasses known in the art.

FIG. 3 shows a flowchart for an improved method for determiningrefractive prescription of eyeglasses in accordance with someembodiments.

FIG. 4 shows a block diagram of an improved system for determiningrefractive prescription of eyeglasses in accordance with someembodiments.

FIG. 5 shows a block diagram of an improved system for determiningrefractive prescription of eyeglasses in another embodiment of thepresent disclosure.

FIG. 6 shows a block diagram of an improved system for determiningrefractive prescription of eyeglasses in yet another embodiment of thepresent disclosure.

FIG. 7 shows a block diagram of an improved system for determiningrefractive prescription of eyeglasses in still another embodiment of thepresent disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference now will be made in detail to embodiments of the disclosedinvention, one or more examples of which are illustrated in theaccompanying drawings. Each example is provided by way of explanation ofthe present technology, not as a limitation of the present technology.In fact, it will be apparent to those skilled in the art thatmodifications and variations can be made in the present technologywithout departing from the scope thereof. For instance, featuresillustrated or described as part of one embodiment may be used withanother embodiment to yield a still further embodiment. Thus, it isintended that the present subject matter covers such modifications andvariations as come within the scope of the appended claims and theirequivalents.

FIG. 2 shows a recently developed method for customized refractivecorrection based on wavefront measurement, related to methods describedin U.S. Pat. No. 8,419,185, U.S. Pat. No. 8,827,448, and U.S. patentapplication Ser. No. 14,465,755 entitled “Methods and Devices forRefractive Correction of Eyes,” all of which are incorporated herein byreference. First, a wavefront aberrometer 21 is used to measure allrefractive errors of an eye. A wavefront aberrometer is more accuratethan a conventional autorefractor because it uses a wavefront sensor toprecisely measure not only the focus error and astigmatism (a cylinderpower and a cylinder angle), but also other higher order aberrationssuch as coma, spherical aberration, and all the other irregularaberrations in an eye. Second, a wavefront prescription 22 is generatedfor the tested eye with a wavefront-optimized spherical power F_(s), awavefront-optimized cylinder power F_(c), and a wavefront-optimizedcylinder angle F_(a). Because of the high accuracy of the wavefrontsensor as well as wavefront optimization with all the higher-orderaberrations, the wavefront-optimized cylinder power F_(c) and thewavefront-optimized cylinder angle F_(a) of the eye are thus finalizedwith the wavefront refraction. Third, a phoropter 23 is used for asubjective optimization. Operators (e.g., optometrists or opticians) setthe phoropter according to the objective wavefront refraction, and askthe tested subjects (patients) to subjectively optimize the sphericalpower. With the tested subject viewing an acuity chart, an opticalprofessional (which shall also be used interchangeably with the termsoptometrist or optician for the purposes of this disclosure) will modifythe spherical power based on feedback of the patient being tested. Thesame process is repeated for the other eye of the tested subject. Third,the final prescription 24 of the eyeglasses is determined for each eyewith the subjectively optimized spherical power F_(s), the wavefrontoptimized cylinder power F_(c), and the wavefront optimized cylinderangle F_(a).

The wavefront method in FIG. 2 does improve vision beyond theconventional refraction in FIG. 1. However, similar to the conventionalsubjective refraction in FIG. 1, it is a different matter whether thetested subject will like the improved vision with the pair ofwavefront-customized eyeglasses.

Lenses of eyeglasses are usually 12.5 mm in front of the corneal vertexof human eyes while the nodal points of human eyes are about 7 mm behindthe coneal vertex in human anatomy. This distance from lenses to thenodal points of 19.5 mm leads to demagnification of retinal images fornegative lenses (myopia correction) and magnification of retinal imagesfor positive lenses (hyperopia correction) with the eyeglasses. Toriclenses with cylinder powers in eyeglasses having different refractivepower in the two principal meridians will cause a magnificationdifference in the two principal meridians, and leads to image distortionof eyeglasses. This image distortion cannot be detected in therefraction process because the size of acuity chart letters is too smallfor the tested subjects to notice the image distortion, but can havesignificant impact on the experience of new eyeglasses for comsumers.

This problem of image distortion certainly not only is unable to beaddressed with the wavefront refraction techique in FIG. 2 in the priorart, but also cannot be handled by the conventional refraction techiquein FIG. 1 as well.

The conventional refraction process as shown in FIG. 1 relies on theexperience and skills of an individual optometrist (optician) to set thestarting as well as the ending cylinder power for the eyeglasses. Thisconventional approach has at least three drawbacks. First, the process,relying on the experience of an optical professional, is not scientificand thus optimized results are usually not obtained. Second, the processcannot be standardized because each optical professional has his/her ownexperience in the past, which will also change over time for eachoptical professional. Third, the process does not take into accountindividual tolerence of image distortion, and people get a “one sizefits all” solution by an individual optometrist or optician even thoughthis certainly should not be.

The present disclosure includes methods and systems for reducing oreliminating image distortion of eyeglasses.

In one embodiment, an improved method for determining refractiveprescription for eyeglasses is described as shown in FIG. 3.

In the first step 31 of FIG. 3, an objective refraction device is usedto measure refractive errors of a human eye objectively. The objectiverefraction device, which excludes—that is, does not involve—subjectivefeedback from the tested subject, should provide accurate and objectivemeasurement of refractive errors of eyes 32. The refractive errors mayinclude a focus error, a cylinder error, a cylinder power, coma, andspherical aberration in an eye. In the second step 33 a/33 b, aplurality of objective prescriptions is generated from the refractiveerrors of a human eye measured objectively. In one embodiment, aplurality of objective prescriptions includes at least a first objectiveprescription 33 a having a first objectively determined spherical powerF_(s1), a first objectively determined cylinder power F_(c1), and afirst objectively determined cylinder angle F_(a1); and a secondobjective prescription 33 b having a second objectively determinedspherical power F_(s2), a second objectively determined cylinder powerF_(c2), and a second objectively determined cylinder angle F_(a2). Inone embodiment, the first objective prescription is optimized for imagequality—e.g., to offer the best image quality—while the second objectiveprescription is determined for a reduced image quality compared to thatof the first objective prescription, or for obtaining reducedmagnification differences at different orientations. In someembodiments, more than two objective prescriptions 33 a, 33 b may begenerated.

In the third step of FIG. 3, a phoropter 34 (which may also be referredto as a phoropter module in this disclosure) is used to performsubjective refraction, to determine a plurality of subjective sphericalpowers subjectively. In one embodiment, a plurality of subjectivespherical powers includes at least a first subjectively-optimizedspherical error f_(s1) (35 a), and a second subjectively-optimizedspherical power f_(s2) (35 b). Note that the term spherical power isalso known in the industry as focus power. The phoropter 34, placed infront of the eyes of the test subjects to see through so that differentcorrection lenses can be selected for the correction of focus error aswell as cylinder error, includes a plurality of spherical lenses andcylindrical lenses. The test subject, seeing through the lenses in thephoropter, provides feedback about what he/she can recognize on anacuity chart. The operator (a optometrist or an optician) is onlyallowed to change the spherical power of the phoropter and to switchbetween the objective perscriptions previously generated prior to step34. Control of cylinder lenses in the phoropter is based only on theplurality of objective prescriptions generated automatically (e.g., 33a, 33 b), and the cylinder lenses are prohibited from being changed bythe operator. That is, when using the phoropter in step 34, sub-step 37involves selecting one of the objective refractions 33 a or 33 b. Theoptical professional provides a spherical power setting in sub-step 38.The phoropter thus can present to the patient two options in sub-step39: option 1 using the objective cylinder power F_(c1) and objectivecylinder angle F_(a1) with the spherical power F_(s)+δF_(s) (δrepresenting an adjustment made in the subjective assessment), or option2 using the objective cylinder power F_(c2) and objective cylinder angleF_(a2) with the spherical power F_(s)+δF_(s). Before the spherical poweris subjectively optimized, the spherical power is adjusted in sub-step38 and the subjective assessment is repeated using the settingsindicated in sub-step 39 until the spherical power is optimized for theprescription option (option 1 or 2) that is being assessed. After thespherical power assessment for one option has been completed, the otheruntested prescription is selected in sub-step 39 b and the process isrepeated. Once the spherical power has been subjectively optimized forboth option 1 and option 2, option 1 and option 2 are finished, withoption 1 resulting in the first subjectively-optimized spherical errorf_(s1) (35 a) and option 2 resulting in the secondsubjectively-optimized spherical power f_(s2) (35 b).

In the fourth step of FIG. 3, a plurality of prescriptions foreyeglasses is generated including at least a first prescription foreyeglasses 36 a with a first subjective spherical power f_(s1), a firstobjective cylinder power F_(c1), and a first objective cylinder angleF_(a1); and a second prescription 36 b with a second subjectivespherical power f_(s2), a second objective cylinder power F_(c2), and asecond objective cylinder angle F_(a2). In some embodiments, more thantwo prescriptions for eyeglasses 36 a, 36 b can be generated. Theseprescriptions for eyeglasses can then be utilized to help a patientselect the optimal choice for reducing or eliminating image distortion.

In one aspect of this embodiment, the method further includes generatinga final prescription for eyeglasses according to a final preferencegiven by the tested subject. Eyeglasses according to the plurality ofprescriptions are realized by a plurality of the trial lenses presentedon one or more eyeglass frames, which are worn on the face of the testedsubject. From wearing the trial lenses, the tested subject can thenselect their final preference for which prescription for eyeglassesprovides the best vision.

The improved method of FIG. 3 overcomes the three drawbacks of theconventional process shown in FIG. 1. First, the improved methodaccording to the present disclosure does not rely on experience ofoptical professionals to handle issues of image distortion, and actuallydoes not allow optometrists/opticians to change the cylinder powers andcylinder angles based on their experience and skills. This makes therefraction process standardized. Second, instead of obtaining only a“one solution fits all” prescription in the conventional process byoptometrists or opticians as in FIG. 1 and wavefront customizedprescription in FIG. 2, the improved method provides at least twodifferent solutions that are different for the effect of imagedistortion. This allows the individual consumer to find the besteyeglasses without noticing image distortion. This solves the problem ofindividual difference in tolerance of image distortion. Third, theimproved method can provide objectively optimized results based onscientific calculation. Differences in cylinder power or cylinder anglein a plurality of prescriptions are objectively determined based on anumber of factors including but not limted to 1) ratio of the sphericalpower to the cylinder power for an eye according to refractive errors ofan eye measured objectively, which allows automatic and precisecalculation of a ratio of magnification in each prescription by a personof ordinary skill in the art, and provides solutions with differentlevels of image distortion; 2) the relationship between coma andcylinder power and cylinder angle in an eye; 3) absolute value ofcylinder power according to refractive errors of eye measuredobjectively; 4) absolute value of cylinder angle according to refractiveerrors of an eye measured objectively; 5) the relationship betweencylinder angles in both eyes of the same tested subjects because thefinal image distortion of a pair of eyeglasses will be determined byperception by both eyes through a pair eyeglasses; and 6) the cylinderpower and cylinder angle of a pair of old eyeglasses worn previously bythe tested subject, which represents the prior level of image distortionthat has been experienced by the tested subject.

In some embodiments, the objective refraction device involves measuringwavefront aberration of an eye, and the wavefront aberration includescoma and spherical aberration in the eye.

In some embodiments, a plurality of objective prescriptions generatedare different in cylinder power, and/or are different in cylinder angle.For example, the first objective cylinder power F_(c1) and the secondobjective cylinder power F_(c2) are different from each other. In otherembodiments, the first objective cylinder angle F_(a1) and the secondobjective cylinder angle F_(a2) are different from each other.

In some embodiments, the method is further configured to take intoaccount refraction data for the left and right eyes of the testedsubject, or refraction data of an old pair of eyeglasses worn by thetested subject before.

In some embodiments, the final prescription for eyeglasses furtherincludes a spherical aberration.

In yet other aspects, the methods in the present disclosure includes aninformation processing method for a system for determining refractiveprescription of eyeglasses.

FIG. 4 shows a block diagram of an embodiment of a system 40 used forimplementing the improved method in FIG. 3, for determining refractiveprescription of eyeglasses for human subjects. The system 40 comprises amodule of objective refraction 41 that measures refractive errors of ahuman eye objectively. Objective measurement does not involve anysubjective feedback of the tested subject. The objective refractionmodule or device 41 can be, for example, a wavefront aberrometer thatmeasures all aberrations of an eye including a focus error, acylindrical error, a cylinder angle, spherical aberration and coma in aneye. In some embodiments, objective refraction device 41 can also be animproved autorefractor that is capable of precisely measuring the focuserror and cylinder error of an eye. System 40 also includes acomputation module 42 that generates a plurality of objectiveprescriptions from the refractive errors of a human eye measuredobjectively. In one embodiment, the plurality of objective prescriptionsincludes at least a first objective prescription 43 a with a firstobjective spherical power F_(s1), a first objective cylinder powerF_(c1), and a first objective cylinder angle F_(a1); and a secondobjective prescription 43 b with a second objective spherical powerF_(s2), a second objective cylinder power F_(c2), a second objectivecylinder angle F_(a2). In one embodiment, the first objectiveprescription 43 a is optimized for image quality, such as to offer thebest image quality, while the second objective prescription 43 b isdetermined for a reduced image quality compared to that of the firstobjective prescription, or for obtaining reduced magnificationdifferences at different orientations.

System 40 also includes a phoropter module 44 that utilizes theplurality of objective prescriptions 43 a, 43 b from the computationmodule 42. Phoropter module 44 is configured to perform a subjectiverefraction, for determining a plurality of subjective spherical powerssubjectively based on the plurality of objective prescriptions. In oneembodiment, a plurality of subjective spherical powers include at leasta first subjective spherical power 45 a (f_(s1)), and a secondsubjective spherical power 45 b (f_(s2)). The phoropter 44, whichincludes a plurality of spherical lenses and cylindrical lenses andcontrol of the cylinder lenses, is placed in front of eyes of the testsubject to see through so that different correction lenses can beselected for the correction of focus error as well as cylinder error inan eye. Test subjects see through the lenses in the phoropter andprovide feedback about what he/she can recognize on a chart such as anacuity chart. The operator (a optometrist, optician, or even the testedsubject) is only allowed to change spherical power of the phoroptor.Control of cylinder lenses in the phoropter is based on the plurality ofobjective prescriptions generated automatically only, and is prohibitedfrom being changed by an operator. The subjective refraction requiressubjective feedback of the tested subject reading a chart through thephoropter and providing subjective feedback.

System 40 also includes an output module 46 for generating a pluralityof prescriptions for eyeglasses including at least a first prescription47 a and a second prescription 47 b. First prescription includessubjective spherical power f_(s1), first objective cylinder powerF_(c1), and first objective cylinder angle F_(a1). Second prescription47 b includes second subjective spherical power f_(s2), second objectivecylinder power F_(c2), and second objective cylinder angle F_(a2).

In some embodiments, the objective refraction device 41 involvesmeasuring wavefront error of an eye using a lens array wavefront sensor.

In some embodiments, the plurality of objective prescriptions 43 a, 43 bthat are generated are different in cylinder power, and/or are differentin cylinder angle.

In some embodiments, the prescriptions for eyeglasses 47 a and 47 b ofsystem 40 is further configured to take into account refraction data fora left eye and a right eye of the tested subject, or refraction data ofold eyeglasses worn by the tested subject before.

In some embodiments, the final prescriptions 47 a, 47 b for eyeglassesfurther include a spherical aberration.

In yet another embodiment, FIG. 5 shows a block diagram of a system 50for generating the plurality of objective prescriptions. System 50 is asub-system of FIG. 4, for determining refractive prescription ofeyeglasses for human subjects. The system 50 includes a module ofobjective refraction 51 that measures refractive errors of a human eyeobjectively, and a computation module 52. Objective measurement does notinvolve any subjective feedback of the tested subject. The objectiverefraction device 51 can be, for example, a wavefront aberrometer thatmeasures all aberrations of an eye including focus error, cylindricalerror, spherical aberration and coma. Objective refraction device 51 canalso be an improved autorefractor that is capable of precisely measuringfocus error and cylinder error. System 50 also includes a computationmodule 52 that generates a plurality of objective prescriptions from therefractive errors of a human eye measured objectively by objectiverefraction device 51. In one embodiment, a plurality of objectiveprescriptions includes at least a first objective prescription 53 a anda second objective prescription 53 b. First objective prescription 53 ahas a first objective spherical power F_(s1), a first objective cylinderpower F_(c1), and a first objective cylinder angle F_(a1). Secondobjective prescription 53 b has a second objective spherical powerF_(s2), a second objective cylinder power F_(c2), and a second objectivecylinder angle F_(a2).

In some aspects of this embodiment, the plurality of objectiveprescriptions 53 a, 53 b that are generated are different in cylinderpower, and/or are different in cylinder angle.

In some aspects of this embodiment, the plurality of objectiveprescriptions 53 a and 53 b of system 50 is further configured to takeinto account refraction data for the left and right eyes of the testedsubject, or refraction data of eyeglasses previously worn by the testedsubject.

In some aspects of this embodiment, the plurality of objectiveprescriptions 53 a, 53 b further include a spherical aberration.

In some aspects of this embodiment, the system 50 is further configuredto be combined with a phoropter module for subjective refinement of aplurality of objective prescriptions, particularly for the subjectiverefinement (refraction) of the spherical powers.

In yet another embodiment, FIG. 6 shows a system 60 in which an inputdevice is used for receiving refractive data for eyes. System 60 is amodified sub-system of FIG. 4 as well, for determining refractiveprescription of eyeglasses for human subjects. The system 60 includes aninput device module 61 configured to receive a refractive data set of aneye, the refractive data set including at least an input sphericalpower, an input cylinder power and an input cylinder angle, and may alsoinclude coma and spherical aberration in the eye. A computation module62 of system 60 generates a plurality of initial prescriptions from thereceived refractive data set of an eye. In one embodiment, a pluralityof initial prescriptions generated from the received refractive data setincludes at least a first and a second initial prescription 63 a and 63b. First initial prescription 63 a has a first initial spherical powerF_(s1), a first initial cylinder power F_(c1), and a first initialcylinder angle F_(a1). Second initial prescription 63 b has a secondinitial spherical power F_(s2), a second initial cylinder power F_(c2),and a second initial cylinder angle F_(a2). In one embodiment, the firstinitial prescription is optimized for image quality, such as to offerthe best image quality, while the second initial prescription isdetermined for a reduced image quality when compared to that of thefirst initial prescription, or for obtaining reduced magnificationdifferences at different orientations. In some embodiments, more thantwo initial prescriptions 63 a and 63 b may be generated.

A phoropter module 64 takes the plurality of initial prescriptions(e.g., 63 a and 63 b) from the computation module 62. Phoropter module64 is configured for determining a plurality of spherical powerssubjectively. In one embodiment, a plurality of subjective sphericalpowers includes at least a first subjective spherical power 65 a f_(s1),and a second subjective spherical power 65 b f_(s2). The phoropter 64,placed in front of the eyes of the test subject to see through so thatdifferent correction lenses can be selected for the correction of focuserror as well as cylinder error in an eye, contains of a plurality ofspherical lenses and cylindrical lenses. The test subject, seeingthrough the lenses in the phoropter, provides feedback about what he/shecan recognize on an acuity chart. The operator (a optometrist or anoptician) is only allowed to change the spherical power of thephoropter. Control of cylinder lenses in the phoropter is based only onthe plurality of objective prescriptions generated automatically, and isprohibited from being changed by an operator.

System 60 also includes an output module 66 for generating a pluralityof prescriptions for eyeglasses, the plurality of prescriptionsincluding at least a first prescription 67 a with the subjectivespherical power f_(s1), the first initial cylinder power F_(c1), and thefirst initial cylinder angle F_(a1). The plurality of prescriptions foreyeglasses also includes at least a second prescription 67 b with thesecond subjective spherical power f_(s2), the second initial cylinderpower F_(c2), and the second initial cylinder angle F_(a2). As inprevious embodiments, the plurality of prescriptions may include morethan two prescriptions 67 a, 67 b.

In some aspects of this embodiment, the input device module 61 includesbut is not limited to one of the following: a keyboard, a touch screen,or a touch-free electronic communication from another device.

In some aspects of this embodiment, a plurality of initial prescriptions63 a and 63 b that are generated are different in cylinder power, and/orare different in cylinder angle.

In some aspects of this embodiment, the prescriptions for eyeglasses 67a and 67 b take into account refraction data for the left and right eyesof the tested subject, or refraction data of an old set of eyeglassesworn previously by the tested subjects.

In some aspects of this embodiment, the plurality of prescriptions foreyeglasses 67 a and 67 b further include a spherical aberration in aneye.

In still another embodiment, FIG. 7 shows a system 70 for determiningrefractive prescription of eyeglasses for human subjects. The systemincludes an input device module 71 that is configured to receive aplurality of initial prescriptions. In one embodiment, the plurality ofinitial prescriptions includes at least a first initial prescription 72a with a first initial spherical power F_(s1), a first initial cylinderpower F_(c1), and a first initial cylinder angle F_(a1); and a secondinitial prescription 72 b with a second initial spherical power F_(s2),a second initial cylinder power F_(c2), and a second initial cylinderangle F_(a2). System 70 includes a phoropter module 73 that receives theplurality of initial prescriptions 72 a, 72 b from the input devicemodule 71.

Phoropter module 73 is configured for determining a plurality ofsubjective spherical powers subjectively; that is, to perform asubjective refraction. In one embodiment, a plurality of subjectivespherical powers includes at least a first subjective spherical power 74a (f_(s1)), and a second subjective spherical power 74 b (f_(s2)). Thephoropter 73, placed in front of eyes of the test subject to see throughso that different correction lenses can be selected for the correctionof focus error as well as cylinder error in an eye, contains a pluralityof spherical lenses and cylindrical lenses. The test subject, seeingthrough the lenses in the phoropter, provides feedback about what he/shecan recognize on an acuity chart. The operator (a optometrist or anoptician) is only allowed to change the spherical power of thephoroptor, by adjusting the spherical lenses. Control of cylinder lensesin the phoropter is based on the plurality of objective prescriptionsgenerated automatically only, and is prohibited from being changed bythe operator.

An output module 75 generates a plurality of prescriptions foreyeglasses including at least a first prescription 76 a with thesubjective spherical power f_(s1), the first initial cylinder powerF_(c1), and the first initial cylinder angle F_(a1); and a secondprescription 76 b with the second subjective spherical power f_(s2), thesecond initial cylinder power F_(c2), and the second initial cylinderangle F_(a2).

In some aspects of this embodiment, the input device 71 includes but isnot limited to one of the following: a keyboard, a touch screen, or atouch-free electronic communication from another device.

In some aspects of this embodiment, the prescriptions for eyeglasses 76a and 76 b take into account refraction data for the left and right eyesof the tested subject. The prescriptions for eyeglasses 76 a and 76 bmay also take into account refraction data of an old pair of eyeglassesworn by the tested subject before.

In some aspects of this embodiment, the plurality of prescriptions 76 a,76 b for eyeglasses further includes spherical aberration in the eye.

While the specification has been described in detail with respect tospecific embodiments of the invention, it will be appreciated that thoseskilled in the art, upon attaining an understanding of the foregoing,may readily conceive of alterations to, variations of, and equivalentsto these embodiments. These and other modifications and variations tothe present invention may be practiced by those skilled in the art,without departing from the scope of the present invention, which is moreparticularly set forth in the appended claims. Furthermore, thoseskilled in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention.

What is claimed is:
 1. A system for determining refractive prescriptionof eyeglasses, comprising: an input device module configured to receivea refractive data set of an eye of a tested subject; a computationmodule configured to generate a plurality of initial prescriptions forthe eye from the refractive data set, wherein: the plurality of initialprescriptions comprises (i) a first initial prescription having a firstinitial spherical power F_(s1), a first initial cylinder power F_(c1),and a first initial cylinder angle F_(a1), and (ii) a second initialprescription having a second initial spherical power F_(s2), a secondinitial cylinder power F_(c2), and a second initial cylinder angleF_(a2); and the first initial cylinder power F_(c1) and the firstinitial cylinder angle F_(a1) of the first initial prescription areoptimized for image quality, and the second initial cylinder powerF_(c2) and the second initial cylinder angle F_(a2) of the secondinitial prescription are determined for a reduced image quality whencompared to that of the first initial prescription, or for obtainingreduced magnification differences at different orientations; a phoroptermodule configured to perform a subjective refraction for determining aplurality of subjective spherical powers based on the plurality ofinitial prescriptions, wherein the plurality of subjective sphericalpowers comprises a first subjective spherical power f_(s1) and a secondsubjective spherical power f_(s2); wherein the phoropter modulecomprises a plurality of spherical lenses and cylindrical lenses,wherein control of the cylindrical lenses is based only on the pluralityof initial prescriptions; wherein the subjective refraction requiressubjective feedback from the tested subject reading a chart through thephoropter module; and an output module configured to generate aplurality of prescriptions for eyeglasses from the plurality of initialprescriptions and the subjective refraction, the plurality ofprescriptions comprising (a) a first prescription having the firstsubjective spherical power f_(s1), the first initial cylinder powerF_(c1), and the first initial cylinder angle F_(a1), and (b) a secondprescription having the second subjective spherical power f_(s2), thesecond initial cylinder power F_(c2), and the second initial cylinderangle F_(a2).
 2. The system of claim 1 wherein the refractive data setcomprises an input spherical power, an input cylinder power and an inputcylinder angle.
 3. The system of claim 1 wherein the refractive data setcomprises coma and spherical aberration.
 4. The system of claim 1wherein the first initial cylinder power and the second initial cylinderpower are different from each other.
 5. The system of claim 4 whereinthe plurality of initial prescriptions takes into account at least oneof (i) refraction data for a left eye and a right eye of the testedsubject, and (ii) refraction data of eyeglasses previously worn by thetested subject.
 6. The system of claim 1 wherein the first initialcylinder angle and the second initial cylinder angle are different fromeach other.
 7. The system of claim 6 wherein the plurality of initialprescriptions takes into account at least one of (i) refraction data fora left eye and a right eye of the tested subject, and (ii) refractiondata of eyeglasses previously worn by the tested subject.
 8. The systemof claim 1 wherein the input device module comprises one of the groupconsisting of: a keyboard, a touch screen, and a touch-free electroniccommunication from another device.
 9. The system of claim 1 wherein theplurality of prescriptions for eyeglasses further comprises a sphericalaberration.
 10. A system for determining refractive prescription ofeyeglasses, comprising: an input device module configured to receive aplurality of initial prescriptions of a tested subject, wherein theplurality of initial prescriptions comprises (i) a first initialprescription having a first initial spherical power F_(s1), a firstinitial cylinder power F_(c1), and a first initial cylinder angle F_(a2)and (ii) a second initial prescription having a second initial sphericalpower F_(s2), a second initial cylinder power F_(c2), and a secondinitial cylinder angle F_(a2); a phoropter module configured to performa subjective refraction for determining a plurality of subjectivespherical powers based on the plurality of initial prescriptions,wherein the plurality of subjective spherical powers comprises a firstsubjective spherical power f_(s1) and a second subjective sphericalpower f_(s2); wherein the phoropter module comprises a plurality ofspherical lenses and cylindrical lenses, wherein control of thecylindrical lenses is based only on the plurality of initialprescriptions; wherein the subjective refraction requires subjectivefeedback from the tested subject reading a chart through the phoroptermodule; and an output module configured to generate a plurality ofprescriptions for eyeglasses from the plurality of initial prescriptionsand the subjective refraction, the plurality of prescriptions comprising(a) a first prescription having the first subjective spherical powerf_(s1), the first initial cylinder power F_(c1), and the first initialcylinder angle F_(a1), and (b) a second prescription having the secondsubjective spherical power f_(s2), the second initial cylinder powerF_(c2), and the second initial cylinder angle F_(a2).
 11. The system ofclaim 10 wherein the input device module comprises one of the groupconsisting of: a keyboard, a touch screen, and a touch-free electroniccommunication from another device.
 12. The system of claim 10 whereinthe plurality of prescriptions for eyeglasses further comprises aspherical aberration.